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Right Triangles and Trigonometry Videos 37 videos
Mosquitos need their caffeine, just like the rest of us. Wouldn't think zipping around and stinging people all day long sap your energy?
ACT Math Trigonometry Drill 1, Problem 2. Can you find the tangent?
ACT Math: Trigonometry Drill 1, Problem 3. Can you find the cosine?
ACT Math 5.3 Trigonometry 192 Views
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Description:
ACT Math: Trigonometry Drill 5, Problem 3. What is the length of side x?
Transcript
- 00:02
Here's your shmoop du jour...
- 00:05
cos(A) = 3/7. What is the length of side x?
- 00:09
And here are your options...
- 00:14
Okay, so we know the cosine of angle A...
- 00:16
and we need to use it to find the length of side x...
Full Transcript
- 00:20
The cosine of an angle is equal to the adjacent side over the hypotenuse.
- 00:24
If the adjacent side is 3 and the hypotenuse is 7, we can use the Pythagorean theorem to
- 00:29
solve for the missing leg, x.
- 00:37
So we can just plug our numbers into this formula,
- 00:39
Three squared plus x squared equals seven squared.
- 00:43
9 plus x squared equals 49.
- 00:49
x squared equals 40.
- 00:53
x equals the square root of 40.
- 00:55
The square root of 40 is equal to 2 root 10, and there you have it...
- 00:59
...option C. That's the way to go.
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